The identification and isolation of useful portions of the genome requires extensive expenditure of time and financial resources. Currently, many genome projects sequence genes use various strategies to reduce cloning and sequencing times. While genome projects rapidly expand the database of genetic material, such projects often lack the ability to integrate the information with the biology of the cell or organism from which the genes were isolated. In some instances, coding regions of newly isolated genes reveal sequence homology to other genes of known function. This type of analysis can, at best, provide clues as to the possible relationships between different genes and proteins. Genomic projects in general, however, suffer from the inability to rapidly and directly isolate and identify specific, yet unknown, genes associated with particular a biological process or processes.
The evaluation of the function of genes identified from genomic sequencing projects requires cloning the discovered gene into an expression system suitable for functional screening. Transferring the discovered gene into a functional screening system requires additional expenditure of time and resources without a guarantee that the correct screening system was chosen. Since the function of the discovered gene is unknown or only surmised by inference to related genes, the chosen screening system may not have any relationship to the biological function of the gene. Further, if negative results are obtained in the screen, it can not be easily determined whether 1) the gene or gene product is not functioning properly in the screening assay or 2) the gene or gene product is directly or indirectly involved in the biological process being assayed by the screening system.
Consequently, there is a need to provide methods and compositions for rapidly isolating portions of genomes associated with a known biological process and to screen such portions of genomes for activity without the necessity of transferring the gene of interest into an additional screening system.